Minnesota Crop News

Eric Yu, Extension Educator – IPM Crops, Dave Nicolai, Extension Educator – Crops As harvest approaches, now is a good time to scout fields and field edges for weeds that escaped earlier control. Mowing fence lines, field edges and other non-crop areas can help prevent weeds from producing seed and reduce the potential for weed seeds to move into fields during harvest. Despite the drier conditions across much of Minnesota this year, weeds continue to emerge and develop in fields and along field edges. Take time now to identify and manage these weeds before they produce additional seed and replenish the soil seedbank. Scout for escaped weeds Many weeds in corn and soybean fields are flowering or developing seed. Pay particular attention to waterhemp and other pigweed species, giant and common ragweed, kochia, common lambsquarters and annual grasses. Waterhemp is especially important to manage because it can produce viable seed within 10 days of pollination and is capable of producing hu...

Robert Koch, Extension Soybean Entomologist, Eric Yu, Extension Educator – IPM Crops Midsummer heat helped keep soybean aphid populations in check across much of Minnesota, as temperatures above 90°F can limit aphid reproduction and survival. However, more moderate temperatures have recently created favorable conditions for aphid population growth, and numbers are increasing rapidly in some areas. Rainfall has also been uneven across the state. While some areas have received much-needed moisture during pod and seed development, other soybean fields remain under significant drought stress. These dry conditions can also favor two-spotted spider mites, making careful, field-by-field scouting important. Below are several considerations for scouting and managing soybean aphids as fields approach the later reproductive growth stages. Scouting strategies Continue scouting based on soybean growth stage rather than the calendar. Aphid populations can continue to increase late in the season, par...

By: Brad Carlson, Extension educator Urea is now the most used nitrogen (N) fertilizer source in Minnesota. The switch away from anhydrous ammonia (NH3) has occurred for many reasons. Some of these include safety of the product, needing specialized equipment for storing, handling and applying, and a narrow range of soil conditions when anhydrous ammonia can be applied. Despite these issues, there are reasons to still consider anhydrous the best source of N in many situations. The science The N content of anhydrous ammonia is 82%, making it the most concentrated N fertilizer available, and therefore the most efficient with respect to its weight and the space it takes up. This means that less product needs to be transported and applied to the field to get the desired N rate. This results in savings of both time and money for the farmer. Anhydrous ammonia is the feedstock from which all other N fertilizers are produced. This means that every other product – such as urea and urea ...

Photo credit: University of Minnesota Extension The benefits and challenges of manure use in general is the topic on this 40th episode of the Advancing Nitrogen Smart podcast series. What is it about manure that makes it good for the soil - and what makes livestock bedding an important addition? What's in manure that's organic but isn't living? What makes the benefits of manure usage long-term in nature? How should people think about manure use related to water quality issues? What kinds of tech might farmers want to be on the lookout for which affect manure use efficiency? According to panelist Melissa Wilson, manure is like a multivitamin for the soil. Find out why she thinks so on today show. Read the full transcript here Guests: Brad Carlson, Extension educator (Mankato) Melissa Wilson, Extension manure nutrient management specialist (St. Paul) Additional resources: Manure management How to put together a manure management plan Nitrogen availability of different...

Small grains harvest is progressing at a brisk pace, and so is the harvest of the small grain yield trials.  Only the spring wheat, barley, and oat variety trials in the two northernmost locations in the state are left standing, and those will come off sooner rather than later.  Curious how your varieties fared against the other entries this season? The preliminary results for grain yield of the winter wheat, winter rye, winter triticale, barley, oats, and spring wheat trials have been posted on varietytrials.umn.edu .  Simply follow the link and click on the nested Google Sheet tab labeled '2026 Preliminary Results'.  Check in (early) next week if the data for your favorite location isn't posted yet. I'll keep updating the  Google Sheets more or less the day I have new data in hand (well, actually, in a spreadsheet on my computer...)  Sin-cereal-y, Jochum Wiersma

Join us Wednesday, August 12th  for the final weekly Field Notes webinar of the summer when we welcome Anthony Hanson , Extension Field Crops IPM Educator, and Dean Malvick , Extension Plant Pathologist. Growers have been asking about interesting methods they have heard about for trying to control diseases or insects, such as using hydrogen peroxide or sugar applications on crops. This session will discuss what data exists on these topics. We'll also discuss late-season diseases such as tar spot and southern rust in corn and what has been seen recently, especially in southern Minnesota. If you aren't registered for these free webinars, visit: z.umn.edu/FN2026. Map of confirmed southern corn rust finds as of Aug. 10, 2026 from Corn IPMPIPE website . Some counties in southern Minnesota have had positive reports.   What is Field Notes? Crop producers and agricultural professionals face a host of challenges, including pest issues, agronomic concerns, and soil fertility...